public override void Add()
        {
            using (FormLongTimeAbsence newAbsenceForm = new FormLongTimeAbsence())
            {
                LongTimeAbsence newAbsence = new LongTimeAbsence();
                newAbsenceForm.Entity = newAbsence;

                if (newAbsenceForm.ShowDialog() == DialogResult.OK)
                {
                    m_absenceList.Add(newAbsence);
                }
                UpdateButtonState();
            }
        }
        public override void Add()
        {
            using (FormLongTimeAbsence newAbsenceForm = new FormLongTimeAbsence())
            {
                LongTimeAbsence newAbsence = new LongTimeAbsence();
                newAbsenceForm.Entity = newAbsence;

                if (newAbsenceForm.ShowDialog() == DialogResult.OK)
                {
                    m_absenceList.Add(newAbsence);
                }
                UpdateButtonState();
            }
        }
        public override void Edit()
        {
            LongTimeAbsence absence = FocusedEntity;

            if (absence != null)
            {
                using (FormLongTimeAbsence newAbsenceForm = new FormLongTimeAbsence())
                {
                    newAbsenceForm.Entity = absence;

                    if (newAbsenceForm.ShowDialog() == DialogResult.OK)
                    {
                        m_absenceList.SetEntity(absence);
                    }
                }
                UpdateButtonState();
            }
        }
        public override void Edit()
        {
            LongTimeAbsence absence = FocusedEntity;
            if (absence != null)
            {
                using (FormLongTimeAbsence newAbsenceForm = new FormLongTimeAbsence())
                {
                    newAbsenceForm.Entity = absence;

                    if (newAbsenceForm.ShowDialog() == DialogResult.OK)
                    {
                        m_absenceList.SetEntity(absence);
                    }
                }
                UpdateButtonState();
            }
        }